1. Field of the Invention
The present invention relates to a device for detecting a weld seam on a pipe member which is equipped in a laser beam machine for processing pipe members and the like.
2. Description of the Related Art
Laser beam machines for processing pipe members perform laser processing to pipe members via a laser processing head while rotating a chuck holding the pipe member.
For example, Japanese Patent Application Laid-Open Publication No. 2001-150175 discloses a laser beam machine capable of processing pipes.
The pipe material being subjected to processing can be a cylindrical pipe P1 or a square pipe P2 as illustrated in FIGS. 9A and 9B, and depending on the pipe material, the pipe can be a welded steel pipe in which a steel material is formed into a cylindrical or square pipe shape and the butted portion is bonded via welding.
In this type of welded pipes, weld beads S1 and S2 which are called seams are formed along the axis line of the pipes. The seams deteriorate the appearance of the pipes, so it is preferable not to form the seams on the outer sides of the pipes if possible. In addition, it is often necessary to avoid the seam when subjecting the pipe to laser processing for structural purposes. In these types of laser processing, it is necessary to confirm the position of the seam on the welded pipe and to compute the angle of the pipe to perform processing using the position of the seam as reference.